The primary aim of this research is to examine individual differences in the modifiability of older adults' intellectual performance through training procedures, in persons whose prior intellectual performance through training procedures, in persons whose prior intellectual performance has been documented through their participation in the Seattle Longitudinal Study (SLS). These longitudinal data permit comparison of training effectiveness for subjects who have retained a stable level of functioning over a substantial time period to that of subjects with well documented decline. Thus, the impact of training can be examined on both the reduction of demonstrated age-related deficits (decline) and upon the improvement of existing or learning of new skills. The sample consists of 400 SLS participants including young-old (62-75 years) and old-old (76+ years), with 60% females and 40% males. To examine remediation and/or improvement of intellectual performance with training, subjects will be classified into two group who have demonstrated a stable level of functioning or decline over a prior seven-year period on one of two target abilities to be trained: Spatial Orientation or Inductive Reasoning. Training effects will be assessed for training transfer to a broad battery of intellectual abilities. Multivariate analyses will assess the invariance of ability structure across training, sex, age/cohort, and change status. Effects of flexibility-rigidity upon change status and cognitive training will also be examined. The focus on the differentiation of remediation of cognitive loss and/or improvement of stable level in the elderly is basic to cognitive intervention efforts in a number of applied areas. Such intervention methods have promise for the development and assessment of training programs for older workers; for the design of post-secondary educational programs for older adults; and for work with the elderly suffering from cognitive deficits, such as those associated with early symptoms of senile dementia.